Polymerization of vinylidene compounds in the presence of a catalyst composition comprising dimethylhalophenylhydroperoxymethane



Patented May 12, 195.3

LYST COMPOSITION GOMPRISING DI` ME .T Lili A-D 0 P HENYLHYDROPEROXY- hydroperoxymehne f ef ae -Qidants ff 01j p sefi emulsion polymerizationh reactions', and with 'sri tween 50 and 175 C., although in some instances it might be desirable to operate outside this range, that is, at either higher or lower temperatures. At the conclusion of the reaction the oxidized mixture may be employed as such, that iS, as a solution of the hydropercxymethane in the reaction mixture, or unreacted material may be removed and residual hydroperoxide material employed. Other methods of producing such dimethyl(halophenyl)hydroperoxymethanes can be used, if desired. These hydroperoxide compositions not only give faster polymerization rates when used to eifect emulsion polymerizations, but their use also frequently results in a more uniform reaction rate over a given reaction period than do hydroperoxides heretofore used. These advantages are particularly pronounced at polymerization temperatures below 10 C., and down to polymerization temperatures as low as -30 or 40 C., or lower.

We use the hydroperoxides discussed herein as oxidants in polymerization recipes at low D015- merization temperatures, i. e. from about 10 C., or just above the freezing point of water, to well below the freezing point of water, such as 40 C. or lower. The recipe will also include a compound or composition which will act as a reductant in the presence of such hydroperoxides under the polymerization conditions set forth herein. Apparently the hydroperoxides and such a reductant slowly interract during the course of the polymerization to produce or generate free radicals, which continually initiate chaintype polymerization reactions. In some recipes such a reductant will be a single compound, or a mixture of homologous compounds, such as hydrazine, ethylenediamine, diethylenetriamine, aminoethylethanolamine, ethylenemethylenetriamine, tetraethylenepentamine, and the like. These compounds have the general formula where each R contains not more than eight carbon atoms and is of the group consisting of hydrogen, aliphatic, cycloaliphatic, aromatic, olenic, and cycloolenic radicals, and each X contains not more than three carbon atoms and is of the group consisting of hydrogen and aliphatic radicals, m is an integer between and 8, inclusive, andn is an integer of the group consisting of O and l and is 1 when m is greater than 0. Each of the foregoing radicals (other than hydrogen) can be completely hydrocarbon in character, and can be of mixed character when containing six or more carbon atoms, such as alkylcycloalkyl, aralkyl, alkaryl groups, and the like, and can also have non-hydrocarbon substituents, some of which will have the effect of making them more Water-soluble and less oil (hydrocarbon) -soluble; particularly useful non-hydrocarbon substituents include oxygen in the form of hydroxy and ether compounds, sulfur in similar compounds (i. e. mercapto compounds and thioethers) and halogen compounds. In such recipes, such a polyamino compound appears to act as a reductant, and no other activating ingredients, such as compounds of polyvalent-multivalent metals, or reducing ingredients, such as a reducing sugar, need be present in order to obtain satisfactory and rapid polymerization of the monomeric material, even at subfreezing temperatures. The amount of polyamino compound used to obtain Optimum results also is dependent upon other ingredients in the recipe. Preferred results are usually obtained with between 0.02 to 5 parts by weight,

per 100 parts of monomeric material, of the polyamino compound. In other recipes a composition is used which comprises one compound which is an oxidation catalyst, or activator, and another different compound which is a reductant. The oxidation catalyst is generally selected from a group of materials consisting of compounds 0f metals such as iron, manganese, copper, Vanadium, cobalt, etc. In general it is assumed that the metal must be a multivalent metal and in such a condition that it can change its valence state reversibly. The other ingredient ordinarily present is a reductant, and is usually an organic material such as a reducing sugar or other easily oxidizable organic compound having a hydroxy group on-a carbon atom directly attached to an aldehyde or ketone group. Compounds frequently employed in this capacity are glucose, levulose, sorbose, invert sugar, hydroxy acetone, glyceraldehyde, and other aldoses and ketoses.

. The multivalent metal ion of the oxidation catalyst can easily and readily pass from a low valence state to a higher valence state, and vice versa. Sometimes this compound, when present in its lower valence state, can function in the dual role of reductant and oxidation catalyst. One commonly used oxidation catalyst is an iron pyrophosphate, and is separately made up in aqueous solution from a ferrous salt, such as ferrous sulfate, and a pyrophosphate of an alkali metal, such as sodium or potassium.

When a ferrous pyrophosphate activator is used, it is preferably prepared by admixing a ferrous salt, such as ferrous sulfate, with a pyrophosphate of an alkali metal, such as sodium or potassium, and water and heating this mixture, preferably for the length of time required for maximum activity. A reaction occurs between the salts, as evidenced by the formation of a grayish-green precipitate. When preparing the activator the mixture is generally heated above 50 C., for variable periods depending upon the temperature. For example, if the mixture is boiled, a period of twenty minutes or less is sufcient to produce the desired activity, and the time of boiling may even be as low as 30 seconds. One convenient method of operation involves maintaining the temperature of the activator solution at about 60 C. for a period of heating ranging from 10 to 30 minutes. Prior to heating the activator mixture the vessel is usually flushed with an inert gas such as nitrogen. In general it is preferred to heat the mixture below the boiling point, say at a temperature around 55 to 75 C.

In cases where the activator is prepared just prior to use, it is generally employed in the form of an aqueous dispersion as described above. However, the solid activator may be isolated and the crystalline product used, and in this form it is preferred in some instances. Subsequent to heating the activator mixture, it is cooled to around room temperature and the solid material separated by centrifugation, filtration, or other suitable means, after which it is dried. Drying may be accomplished in vacuo in the presence of a suitable drying agent, such as calcium chloride, and in an inert atmosphere such as nitrogen. When using this crystalline product in emulsion polymerization reactions, it is generally charged to the reactor just prior to introduction of the butadiene. This crystalline material is believed to be a sodium ferrous pyrophosphate complex, such as might be exemplified by the formula 2Na2FeP2Oi-Na4P2O'1, or perhaps NazFePzOi. In

am@ event-fthe ccrnplex whatever itsy composition, is; only slightly* scluhle Water and: is one activeform. oi; ferrous. ion and pyrephesphate. which can be successfully used our invention.. It may be mcorporated. inthe nolyme-rizatien mixture as such, or dissolved sunicient water toproduce solution.. Qther terms of Inultivalent metal. and pyrcphcsnhatemay' alsof be used. S0 long` as. there is present; in. the; reacting mixture.` a soluble. form of' a, multivalent, metaL, capable of existing two.A valence states and. present. Dfimaril-y in the lower of: two; valence,A states, and' a, pyrophosphate.

The. amounts. of, ac ticraterE ingredients are usu ally expressed' interms or the monomers charged. The.y multiyalent metal Should; be Within the ran-ge' oi' `0.10; to. 3: rnilliinols.A per I JQ4 parts by weight of. monomers, with 0.2; to mllliimols.. being; generaliy preferred. The amount of: pyrorhosphate shouldv be. Within. the; rangefcf. Olli). to.- 5.6; r-nill-irnolsV based on. 16.9; parts. by Weight ofl menemers; how-Y ever, the narrower range: et: 0.2; to millimolsi is. more frequently preferred.. The mol ratio of. ferrous salt to. aliraliI metal pyrophosphate can be between. 1:0.2 and 1.:3.5., with a preerredratio between 1:0;35. and l.:2...3..

In eecting emulsion polymerization of a. H1011 omeric. material, particularly when a. bath-WD@ orv semifhatch-type operationisv carried 01115,. the reactor is. usually rst. charged.. with. the; amieousA medium, which contains the desired. emiilsilying` agent, andthe monomeric.- materialf. is then admixed with agitation ot the. contents. .at the same time a` reactior-i-` modier,y such. as. a. mme? tan, is. also included; usually in, solution in at least a part of themonomeric material.. Ana-.ctivator` solution and? an oxidant` are. Separately addedL to the reaction mixture, and reaction. then proceeds. A preferred manner of1'addingthese 13W@A constituents. isi usually: to` have the acjt.iyator solution incorporated in. the acnieous` medium prior to. additionA of." the. monomeric. material,v and.. toi add-the-oxidantas the last-ingredient.. Some: times, however, satisfactory polymerization Ie.- sultscan' be: obtained when this. procedura is; reversed: It is= alsol sometimesthe; practice; to. addpor-tions of one, or the'other ofthe:activator'solurtions=andvcxidant intermittently.orgoontinuously; during the course of. the reaction.. Ifa the oper.- atiorris carriedoutcontinuously; streams .of the various'- ingredientsare'` adniixedf insomewhat the same1order-priorto theirr inal-` introduction .into thev polymerizationreaction Zone:

As previously stated, itis usuallyfdesirableithat the-multivalent metal-L bepresent in itslower val.- ence state. With some;y recipes, itfis. unnecessary; toI include an: organic reducing,` agent. either in theactivator solution'. or.` in the; polymerization mixture. However, particularly` attemperatules above. 0? G., afaster reaction is.. sometimes. Ob.:- tainedwith some recipes.: when. a small:v amount oi' an organic reducing agent, such asgarreducing sugar, is included in thepolymerization recipe, and it is frequently more desirable to incorporate this.; in the; react-1.01.1y System br first including: it intheactiratcrSolution-alonggwith;the other inf sredientsy Whcnithe-multiyalent ion isnt-esem' in i eh' aler-ice-s,tat.e,,it.v is usually., necessary lufthefaetvatcr solutionanrgae i eene` Asa result.themuitivalentien nartiallr reduced and, ae substantial ernennt 0f -themultraknt iouwilrbeepresent in its..V loyer valence;A State Willem the, actratcmv Selur` The. monomeric, material polymerized to produce polymers by the. process of. this inventionl comprises unsaturated organic compounds. generally contain the characteristic structure. CH2=C` and, in most. cases, havev at least one of the disconnected valencies; attached to an elec,-y

tronegativegroup,` that is, a group. which increases the polar character of the molecule such as achlorine group or an organic group contain.- ing; a double or triple bond such as vinyl,.phenyl' cyano., carboxy or the like. Included in thisclass of monomersv are the conjugated butadienes. 01. 1,3-butadienes` such. as butadiene. (L3-butadiene). as-dimetnyi-iis-butadiene, isoprene, piperylene, 3.furyl-l,3butadiene, 3-methoXy-'L3-butadiene. and theI lilre;` haloprenes, such as` chlorop-rene (f2.-chl'oro.f-l.,3-hutadiene), bromoprene, methylchloroprene (2-chloro-3-methylrlehutadiene andthe like; arylolens such. as styrene, Various. alyk-yl' styrenes. p-ohlorostyrene,l p-methoxystyrene, alpha-methylstyrene,y vinylnaphthalene and.

similar derivatives; thereof.,Y and. the like; acrylicandLv substituted acrylic acids. and. their: esters, nitril'es and amides such. as acrylic. acid methacryl-ic acid,A methyl acrylate, ethyl. acrylate, methyl alpha chloro acrylate, methyl metl-iaeryla-te,Y ethyl methacrylate, butyl methacrylate, methyl ethacrylate, acrylenitrile,` methaerylonitrile, metliacrylamide and. the` like, methyl isopropenyl i ketone,l meth-yl Vinyl ketone,A methyl vinyl ether,

Vi'nylethinyl alkylv carbinols, vinyl acetata, vinyl chloride, vinylidene chlorida vinylfurane, vinylcarbazcle, vinylacetyleneA and other unsaturated hydrocarbons, esters, alcohols, acids, ethers, etc., of. the types. described. Such; unsaturated'-com-- pounds may be. polymerized alone, in` which. case simple linear polymers4 are.- formed, or mixtures of two or more; of. such compounds which are copolymerizalole with eachother. in aqueous'emulr mixture.

sion may. hepolymerized. to; form linear copoly mers.

The process ofv this inventionis particularly eiectiye when; the,monomericmaterial polymer'- izect is a. polymerizable aliphatic-=c onjugated dioleiin or: a mixture of; such a coniugatedidiolen with lesser. amounts of; one ormore other com.- pounds containing an active CHz.=C i group which, are. copolymerizahle therewith such as. aryl cleiins. acrylicv and'. substitutedV acrylic acids; esters, nitriles and; ainidesg.y methyl isopropenyl ketone, vinyl; chloride, andv similar compounds mentionedhereinabove.. nthiscasezthe products of*v the polynieriaaticn'` are high, molecular weight linear polymers and. copolymers whichv are. rubbery: in'` character and` may bee called' synthetic rubber. Althoughy as; can he.V readily deduced from the foregoing. there;` is.` a host, of' possible reactants, the. most; readily and. commercially ayailablemonomersat present aref butadiene itself .y (LEZ-butadiene). and.' styrene. 'If'he e invention will, therefore; he;morepar-ticularlyfy discussedv and exempliil'edz Witln reference.: to these typical react'ants.` With these speciiic monomers, l it: is usually.l preferred to i use themztogetheninf rela.n tive. ratios; cf hutadienept'o.. styrenefbetween; 65: 35 and 9c: l0 by; Weight..

It is generally preferredthatthe emulsionbe of lan oilf in water. type, with the ratio of aqueous medium to monomeric material between about 05:1. and ahoutv 235:1, inparts by. Weight. Itis frequently4 desirable to. include Water-soluble components. in the aqueous phase, particularly Whenthe polymerization temperatures are below freezing. Inorganic salts and alcohol'scan be so used. Alcohols whichare applicable'pwlien operating at low temperatures, comprise watersoluble compounds of both the monohydric and polyhydric types, and include methyl alcohol, ethylene glycol, glycerine, erythritol, and the like. The amount of alcoholic ingredient used in a polymerization recipe must be sufficient to prevent freezing xof the aqueous phase and generally ranges from 20 to 80 parts per 100 parts of monomers charged. In most cases the amount of water employed is suiicient to make the total quantity of the alcohol-water mixture equal 150 to 200 parts. In cases where it is desired to use a larger quantity of the alcohol-water mixture, say around 250 parts, the amount of alcohol may be increased to as much as 120 parts. It is preferred that the alcohol be such that it is substantially insoluble in the non-aqueous phase, and that 90 per cent, or more, of the alcohol present be in the aqueous phase. A high-boiling alcohol such as glycerine is difficult to recover from the resulting serum; a low-boiling alcohol such as methanol is easily removed and frequently preferred. Other aliphatic alcohols which are higher-boiling than methanol, such as a propanol, are frequently less satisfactory. If the resulting latex tends to gel at l-ow reaction temperatures, a larger proportion of aqueous phase should be used. In the practice of the invention suitable means will be necessary to establish and maintain an emulsion and to remove reaction heat to maintain a desired reaction temperature. The polymerization may be conducted in batches, semicontinuously, or continuously. The total pressure on the reactants is preferably at least as great as the total vapor pressure of the mixture, so that the initial reactants will be present in liquid phase. Usually 50 to 98 per cent of the monomeric material is polymerized.

It is one of the outstanding advantages of the use of the hydroperoxides, as disclosed herein, that it is feasible to produce high solids latices, i. e. latices resulting from the use of an amount of aqueous medium in the lower part of the range disclosedI i. e. a ratio of aqueous phase to monomeric material between 0.5: l to 1:1 and an extent of conversion in the higher part of the range disclosed, i. e. from 70 per cent conversion to complete conversion.

Emulsifying agents which are applicable in these low temperature polymerizations are materials such as potassium laurate, potassium oleate, and the like, and salts of rosin acids. However, other emulsifying agents, such as nonionic emulsifying agents, salts of alkyl aromatic sulfonic acids, salts of alkyl sulfatos, and the like which will produce favorable results under the conditions of the reaction, can also be used in practicing the invention, either alone or in admixture with soaps. The amount and kind of emulsier used to obtain optimum results is somewhat dependent upon the relative amounts of monomeric material and aqueous phase, the reaction temperature, and the other ingredients of the polymerization mixture. Usually an amount between about 0.3 and 5 parts per 100 parts of monomeric material will be found to be sufficient.

rIihe pI-I of the aqueous phase may be varied over a rather wide range without producing deleterious eifects on the conversion rate or the properties of the polymer. In general the pf can be within the range of 9 to l2, with the narrower range of 9.5 to 10.5 being most generally preferred, except when a polyamino compound is used as a reductant, in which case a somewhat higher pH should usually be used.

In preparing synthetic rubber by polymerizing conjugated dienes by the process of the invention, it is usually desirable to use a polymerization modifying agent, as is'usually true in other polymerizations to produce synthetic rubber. Preferred polymerization modifiers for use in the process of the present invention are alkyl mercaptans, and these may be of primary, secondary, or tertiary configurations, and generally range from Ca to C16 compounds, but may have more or fewer carbon atoms per molecule. Mixtures or blends of mercaptans are also frequently considered desirable and in many cases are preferred tothe pure compounds. The amount of mercaptan employed will Vary, depending upon the particular compounds or blend chosen, the operating temperature, the freezing point depressant employed, and the results desired. In general, the greater modification is obtained when operating at low temperatures and therefore a smaller amount of mercaptan is added to yield a product of a given Mooney value, than is used at higher temperatures. In the case of tertiary mercaptans, such as tertiary C12 mercaptans, blends of tertiary C12, C111, and C16 mercaptans, and the like, satisfactory modification is obtained with 0.05 to 0.3 part mercaptan per parts monomers, but smaller or larger amounts may be employed in some instances. In fact, amounts as large as 2.0 parts per 100 parts of monomers may be used. Thus the amount of mercaptan is adjusted to suit the case at hand.

The amount of hydroperoxide used to obtain an optimum reaction rate will depend upon the other reaction conditions, and particularly upon the type of polymerization recipe used. The amount is generally expressed in millimols per 100 parts of monomeric material, using in each instance the same units of weight throughout, i. e. when the monomeric material is measured in pounds the hydroperoxide is measured in millipound mols. The same is true for other ingredients of the polymerization recipe. An optimum rate of polymerization is usually obtained with the amount of hydroperoxide between 0.1 and 10 millimols per 100 parts by weight of monomeric material. The hydroperoxide can frequently be easily separated from accompanying materials by converting it to a corresponding salt of an alkali metal, which is usually a crystalline material in a pure or concentrated state at atmospheric temperatures, and separating the salt. This salt can be used as an active form of the hydroperoxide, since it is promptly converted to the hydroperoxide by hydrolysis when the salt is admixed with the aqueous medium of the polymerization reaction mixture.

Advantages of this invention are illustrated by the following examples. The reactants, and their proportions, and the other specific ingredients of the recipes are presented as being typical and should not be construed to limit the invention unduly.

Eample I Dimethyl (chlorophenyl) methane (100 parts) prepared by the alkylation of chlorobenzene with propylene, was oxidized by charging it to a reactor together with 1.3 part of the potassium salt of triisopropylbenzene hydroperoxide, this latter compound being employed as an initiator for the reaction. The temperature was adjusted to C. and dry oxygen introduced over a 5-hour period while the mixture was stirred. The concentration of hydroperoxymethane at this point l 10 was 11.0 per cent by Weight. Portions of this material were used `to supply the resulting di- I Parts bywelgxm methyltchlorophenyl)hydroperoxyrnethane, in Butdjlene '70 the amounts indicated, as the oxidant in the styrene 30 following polymerization recipe 5 Watetotal 130 f .1 Methanol 45 Parts by Welght .Potassium rosin soap, pH 12.2 3.5 Butadlene 72 Potassium fatty acid soap (ORR) 1 .'-5 styrene -f 28 Blend tert-C12, "C11, lC10 alkyl meroaptans '0.25 Wat@ '90m f1 180 10 Hyd'roperoxidfe Variable (0.5 111111111101) Rosln Soap POtaSSlum Salt 4-7 Tetraethyienepentamine 0.19 `(1.0 mii-1111101) Mercaptan blend2 0.25 3:31304 0 5 Dimethyl (chiorophenyl). h y d r o p e roxymethane Variable In one `run the yhydroperoxide was that Vob- Potassium hydroxide 0.037 tained from oxidizingdimethylhlorophenyli- Potassiumv chloride 0 5 l5 mt-ithane 'with 7 per 'cent conversion in 4 hours, Dextrose 1 0 l2 per cent in 0155 hours, and '60 per cent in 24 Activator composition; y hours. In an accompanying run the hydroper- KfiPzOw 0.165 (0.50 miilimoi) oxide used Was obtained from oxidizing '-cumene, Fe'SOdHHgO 0,14 (0 50 mimmol) 20 as discussed herein, with per cent conversion in Water to make 25 parts of Solution d hours', 12 percent in\6.5 hours, and 45 percent f-Irsinteflltg soluionCpH ll'c D l t m' 24 hours l n e D 4 u v C in a tiitieo o'f03 :r: lupsartbyltghtm a p ld 1c mermmfms Example III h Tte activtr conflrosjn was prepaed by 25 Dim'ethyl(dichlorophenyl)methane (100 parte), .ea mg 2' rglx meto hij' ferous Sulftef mms' prepared by the alkylation'ofa mixture oi orthosllmtpyrop Ospha e and Water am@ C for 20 and para-dichiorob-enzene (principally 'the ortho mfl e' Xt t compound) With propylene, VWas voxidized lo'y t e e reo assumo* hydroxlde afd E pints 'charging it to a reactor together with v'one part Wde Ve1` ea ed a; 7 0 C'. for 25 mmul'es 21nd 30 of the potassium salt voi tert-lcut'y-lisopropylbena 1 ed .o tr? sotap so umonthThe mema'ptan dls zene hydroperoxide, this latter compound hein'g so Vet m .e yene Was .en added the tem' employed as an initiator for the reaction. The rfagret amff m1171516 desmed leVeL the 101552" temperature lwas adjusted 'to 13'0VDA and mle n Il? ufe fol-Qwe by th? h/dFQpefold?, oxygen introducedover a 3HE-hour period' while an Ifa'y he. actwator acomposltlol P015 35 the vmixture was stirred. The concentration of merization Was effected at 5 C. The time-oonhydroperoxymethane at ythis point was '1 -43PM version vdata 'are recorded below together with cem by Weight portions of this material were the amounts 0I hydroperoxide employed. For used tojsuppiythe resulting dimethyidiohioropurposes of comparison, a control run Was made phenyl)hydroperoxymethane, yin the amounts inusing cumene hydroperoxide (dimethylphenyi- 40 dicated, as the oxidant in a series of runs using hydroperoxymethane) in an amount previouslyl the polymerization recipe 'given in Example' found to be optimum for the recipe, The procedure of Example I vWas followed for the Hydroperoxymethane Mols Hydro-v Conversion, Percent FeSCMJlhO peroxy-v i Parts methane per. From (Parent Compound) Parts Millimols Mol Fe++ 2Hrs. f5 Hrs. llHrs.

DimethyMchlorophenyD- 1 methane... 0. 0. 375 0.14 0.75 20.8; 50.0y 77.4 Do.-. .I 0.50 0.14 1.0 17.3 53.4 75.1 Dom- 0.75 0.14 1.5 11.3 4.0.4 05.1; Dmcthylphenylmcthano 0 66 0.14 1.3 12.9 31.4 i 49.3

These data show the superiority of dimethylpreparation 0f the CJVOl COmPQSitiOn, 'Charg- (chlorophenyl)hydroperoxymethane over dimething the materials to the reactor., and carrying ylph'enylhydroperoxymethane as an oxidant in 55 Out the polymerization. The tmeeconversien loW temperature emulsion polymerization redalla are recorded belOW togeth" With Ithe actions. amounts oi hydroperoxymethane employed. For purposes of comparison, a control 'run was made Emmpze H v using dimethylphenylmethane in 'an amount 'pre- Polymerization of a monomeric material com- 60 viously found to be optimum for the recipe.

Hydroperoxymethane Mols Hydro- Conversion, Percent FeSO4JH2O peroxy- Parts meth-ane per From (Parent Compound) Parts Milli'mois Mol Fe-If-i- 2 Hrs.V 5 Hrs. 7 Hrs.

DiinctliyMdichloroph 'n 1) methane .Y 0. 084 0. 3s 0.111 0.75 18.4 53.3 77.1 Do 0,11 0.5 0.14 1.0 23.0 05.31 86.1 D0..Y 0.105 0. 75 0.14 1.5 .20.5 75.8 91.7 Do 0 221 1 0 0.14 2.0 2016 58. 8 85.0 Dimethyiphenylmethen@ 0.10 0.05 0.14 1.3 0.o 30,0v 42.1

prisine 1,3-but'adiene and styrene. was carried out, using thefollowing recipe fand a polymerization temperature of -.1 0 Q As will be evident to those skilled in 'the art, various modifications of vthis invention `can be made, or foiiowed, in the iight oi the foregoing ,and maintaining at a polymerization temperature between and 40 C. an emulsion of an aqueous phase having a pH between 9 and 12,

aliquid monomeric material comprising a major amount of 1,3-butadiene and a minor amount of styrene, an alkali metal soap emulsifying agent, an alkyl mercaptan having between eight and sixteen carbon atoms per molecule, and a polymerization catalyst composition comprising 0.1

to 10 millimols of dimethylhlorophenyl) hydroperoxymethane together with 0.1 to 3 millimols of an alkali metal ferrous pyrophosphate complex and a reducing sugar, said parts being parts by weight per 100 parts of said monomeric material.

2. An improved process for the production of ,synthetic rubber, which comprises establishing and maintaining at a polymerization tempera- .ture between 10 and 40 C. an emulsion of an aqueous phase having a pH between 9 and 12, a liquidmonomeric material comprising a major amount of 1,3-butadiene and a minor amount of styrene, an alkali metal soap emulsifying agent,

an alkyl mercaptan having between eight and sixteen carbon atoms per molecule, and a polymerization catalyst composition comprising 0.1 to 10 millimols of a dimethyl(halophenyl)hydro- -peroxymethane containing not more than four halogen atoms each selected from the group consisting of uorine, chlorine and bromine together with 0.1 to 3 millimols of an alkali metal ferrous pyrophosphate complex and a reducing sugar, said parts being parts by weight per 100 parts of vsaid monomeric material.

3. In the production of synthetic rubber by polymerization of a monomeric material comprising a conjugated diene having not more than six carbon atoms per molecule while dispersed in an aqueous medium in the presence of a catalytic composition comprising an oxidant and a reductant, the improvement which comprises polymerizing said monomeric material in the presence of 0.1 to 10 millimols of dimethyl(chloro phenyl)hydroperoxymethane per 100 parts by weight of said monomeric material together with a material which acts as a reductant in the presence of said hydroperoxide under said conditions of polymerization.

4. An improved process for the production of `synthetic rubber, which comprises establishing and maintaining at a polymerization temperature between 10 and 40 C. an emulsion of an aqueous phase having a pH between 9 and 12, a liquid monomeric material comprising a major amount of .L3-butadiene and a minor amount of styrene, an alkali metal soap emulsifying agent, an alkyl mercaptan having between eight and sixteen carbon atoms per molecule, and a polymerization catalyst composition comprising 0.1 to 10 millimols of dimethyl(dichlorophenyl)hydroperoxymethane together with 0.1 to 3 millimols of an alkali metal ferrous pyrophosphate complex and a reducing sugar, said parts being parts by weight per 100 parts of said monomeric material.

l 5. In the polymerization of a monomeric material comprising a conjugated diene havingl not more than six carbon atoms. per molecule while:

dispersed in an aqueous medium in the presence of a catalytic composition comprising an oxidant and a reductant, the improvement which comprises polymerizing said monomeric material in the presence of 0.1 to 10 millimols of dimethyl- (dichlorophenyl)hydroperoxymethane per parts by weight oi said monomeric material together with a material which acts as a reductant in the presence of lsaid hydroperoxide under said conditions of polymerization.

6. In the polymerization of a monomeric material comprising a conjugated diene having not more than six carbon atoms per molecule while dispersed in an aqueous medium in the presence of a catalytic composition comprising an oxidant and a reductant, the improvement which comprises polymerizing said monomeric material in the presence of a dimethyl(halophenyl) hydroperoxymethane containing not more than four halogen atoms each selected from the group consisting of luorine, chlorine and bromine together with a material which acts as a reductant in the presence of said hydroperoxide under said conditions of polymerization.

7. The process of claim 6 in which said hydroperoxymethane is dimethylhlorophenyl) hydroperoxymethane.

8. The process of claim 6 in which said hydroperoxyrnethane is a dimethyl dihalophenyl)hydroperoxymethane.

9. The process of claim 6 in which said hydroperoxymethane is dimethyl dichlorophenyDhydroperoxyinethane.

10. An improved process for polymerizing a monomeric material comprising an unsaturated organic material containingl a CH2=C group and polymerizable when dispersed in an aqueous emulsion in the presence of a polymerization catalyst composition comprising an oxidant and a reductant, which comprises polymerizing such a monomeric material dispersed in an aqueous medium in the presence of such a polymerization catalyst comprising dimethyl(dichlorophenyl hydroperoxymethane as said oxidant.

ll. An improved process for polymerizing a monomeric material comprising an unsaturated organic material containing a CII2=C group and polymerizable when dispersed in an aqueous emulsion in the presence of a polymerization catalyst composition comprising an oxidant and a reductant, which comprises polyunerizing such a monomeric material dispersed in an aqueous medium in the presence of such a polymerization catalyst comprising as said oxidant a dimethyl(halophenyl)hydroperoxymethane containing not more than four halogen atoms each selected from the group consisting of fluorine, chlorine and bromine.

WILLIAM B. REYNOLDS. JOHN E. WICKLAIZ. THOMAS J. KENNEDY.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,446,797 Vaughn et al. Aug. l0', 1948 2,534,447 Hulse Dec. 19, 1950 OTHER REFERENCES Vandenberg et al., Ind. and Eng. Chem., vol. 40, No. 5, May 1948, pages 932, 937.

Shearon, Jr., et al., Ind. and Eng. Chem., vol.

4,0, N0. 5, May 194.8, pages 769-777. 

1. AN IMPROVED PROCESS FOR THE PRODUCTION OF SYNTHETIC RUBBER, WHICH COMPRISES ESTABLISHING AND MAINTAINING AT A POLYMERIZATION TEMPERATURE BETWEEN 10 AND -40* C. AN EMULSION OF AN AQUEOUS PHASE HAVING A PH BETWEEN 9 AND 12, A LIQUID MONOMERIC MATERIAL COMPRISING A MAJOR AMOUNT OF 1,3-BUTADIENE AND A MINOR AMOUNT OF STYRENE, AN ALKALI METAL SOAP EMULSIFYING AGENT, AN ALKYL MERCAPTAN HAVING BETWEEN EIGHT AND SIXTEEN CARBON ATOMS PER MOLECULE, AND A POLYMERIZATION CATALYST COMPOSITION COMPRISING 0.1 TO 10 MILLIMOLS OF DIMETHYL(CHLOROPHENYL) HYDROPEROXYMETHANE TOGETHER WITH 0.1 TO 3 MILLIMOLS OF AN ALKALI METAL FERROUS PYROPHOSPHATE COMPLEX AND A REDUCING SUGAR, SAID PARTS BEING PARTS BY WEIGHT PER 100 PARTS OF SAID MONOMERIC MATERIAL. 